Characterization of the interactions between stromal and haematopoietic progenitor cells in expansion cell culture models.

Development of the long-term culture models of haematopoietic stem cells (HSCs) is one of the important tasks in modern biotechnology. It has been suggested that stromal presence is important for haematopoiesis in vitro and in vivo, but the question remains: whether diffusible factors produced by stromal cells are sufficient for the regeneration of primitive and definitive haematopoietic cells, or direct cell-to-cell contacts of the cultured material with underlying stromal base would be required. During present studies, influence of various feeder layers and feeder layer conditioned media on proliferative, differentiative and clonogenic activity of human AC133+ derived from human umbilical cord blood was investigated.